The shortest answer most people give when faced with the question of “What do you like about GTA games?” is something along the lines of “all the stuff you can do” or “the openness of it all.” With a franchise that’s sold bajillions of copies and generated even more in revenue you’d think that there’s something deeper there; some “it” that you can point to that will explain its remarkable success (and the relative success of its imitators).

With an uneven mix of direct experience, contemporary video game history and a dash of arrogance, let’s take a stab at just what it is that makes GTA the powerhouse that it is. The folks who make the game would probably offer us the rich stories, environments and characters as the magic that makes it all go and a few of your college professors would probably agree with them on that. But those guys wear elbow patches on their sport coats and to say it’s the literary elements of Grand Theft Auto that sets it apart ignores the fundamentals of the medium. Video games are played. We watch, read and listen to all sorts of media with strong stories. The significance of pressing buttons and controlling what you’re going to see, read and hear next is what separates games from everything else. The elements that separate Grand Theft Auto from every other game out there can be broken down to three things:

Back in 2001, Grand Theft Auto III let us drive around a make-believe city, get out of the car and do stuff. That kind of freedom, communicated in a way that everybody could understand, was a seismic shift and the industry has never looked back. To that point, we’d driven around cities in racing games like Need for Speed and walked around shooting stuff like in Resident Evil. Driving through people and traffic to a specific place in a city and getting out of the car to then shoot something? Never like this. It was that you had a choice of cars and a choice of routes and choice of weapons to use in each of those instances that made GTAIII special. You could walk, carjack a van or use an abandoned beater. Any of your choices would be fully supported by the game so that your skill was the only thing that determined your success. All of the vehicles would get you there and all of the weapons would work as long as you had the ability to properly utilize those tools as a gamer. That’s how GTA changed the concept of freedom in video games. Yeah, Halo: Combat Evolved let you rumble around in a heavily armed Warthog jeep and shoot aliens, but sci-fi like that can –and should– make up its own rules on the spot.

Those rules of video games can’t be overstated. The term “sandbox” is popular now as a way of explaining that within certain defined parameters, many gameplay options are there for the taking. Things like gravity, some doors being locked, and roadblocks preventing you from leaving town are some of the easiest “fences” to understand in Grand Theft Auto’s traditional sandbox. Like kids, we learn the limits of what we’re allowed to do and, once understood, we go have fun with all of the things we are allowed to do in the game. Where GTA III introduced this concept, Vice City, San Andreas and the rest added rocket fuel to the possibilities of what we could do with those characters, those stories and those places. Rules in place allow you to add things like parachuting and base jumping because we suddenly understood that there’s a sky up there with enough room for CJ or Niko to operate so let’s do that. As important as the concept of freedom is in this series, the rules that balance it out are crucial. You know how walking through a wall or seeing arm sticking out of a door makes you feel when you’re playing a video game? Yeah rules prevent you from feeling like that. Because the GTA games have such a realistic look to them this both reinforces and tweaks the idea that all of your actions have to be believable. The stuff you do has to count.

The core driving and combat elements of Grand Theft Auto titles are the cake while minigames and diversions are the icing on top. When the franchise is at its best, all of those activities feed, reinforce and flow with each other to the point where it’s just the main character doing what he does at your discretion. Directing Niko to buy guns out of the trunk of a car parked in an alley seems cool and authentic to the life of a thug the first few times you do it. As you advance in Grand Theft Auto IV, having to “tool up” becomes a necessary step you have to take to prepare for other activities. That switch from convenience to necessity is repeated throughout that game and the series as a whole. Stealing a car was a thrill; now it’s just something you do. That sandbox with all of the rules and freedom to it has evolved throughout Grand Theft Auto’s history to the point that amount of things to do, the action awaiting you in the game outstrips available time in the day any responsible person should dedicate to this stuff. Collecting items; collecting cars; customizing your car; customizing your character; building relationships and all of the other activities that do not move the story forward may change from one game to the next but the series is always going to be about the breadth, depth and quality of those activities because they build on each other. You can’t take out a rival or rob a bank in later levels if you don’t have your preferred ways of dealing with challenges. If you like to speed away from enemies, always having fast transportation is key. If you like to slug it out, then your arsenal of weapons is super important. If you like having the option to do either, then that’s two things you’re going to have to spend time developing before you’ll be able to succeed in the game. The things-to-do list in a Grand Theft Auto game is exhaustive because you never know what you’re going to get into.

Grand Theft Auto V is just around the corner and the second go-round on the PS3 and Xbox 360 should yield the very best in visuals and gameplay innovation in the series. The biggest unveil so far is the fact that you’ll be using three playable characters (with unique abilities and hobbies) in GTA V’s story missions. That’s the kind of leap worthy of the Grand Theft Auto franchise.